Veneered door and like product



May30, 1933. E, C LQETSCHER I 1,911,374

VENEERED DOOR AND LIKE PRODUCT 2 Sheets-Shevet 1 Filed June 12, 193C )flmuli May 30 1933- E. c. I oETscHER I VENEERED DOOR AND LIKE PRODUCTmets-Sheet 2 I l l l Il .Or A l l Il, A n. NNNNNNNNNNNNNNNNNN w 7 w 6, 7

'Patented May 3o, 4193.3 l

UNITED STATES EMIL C. LOETSCHER, 0F DUB'UQUE, IOWA V'ENEERED DQOR LIKE:PRODUCT Application led .Tune 12,

This invention relates to improvements 1n construction for wood veneereddoors and like products, and to the process for manu-v facturin vthesame.

The o ject of the invention is to provide a new and novel constructionfor veneered products, such as doors, utilizing paper-thin sheets orplies of Wood as the veneering material, and 'in accordance with thegeneral process described Vin a previous application filed by me on May2, 1980, bearing Serial N o. 449,116.

Heretofore the art of wood veneering has been limited as to thethickness of the veneering materials used, the minimum being about M6 ofan inch in ordinary commercial practice. Veneers of lesser thickness andapproaching the texture of paper, although readily obtainable incommercial quantities and at a fraction of the cost of the thickerplies, have never found a practical use in the wood-Working industry,and particularly for veneering purposes. One reason for this isA thefact that veneering has been primarily a gluin operation, and thinsheets cannot be satis actorily glued. Again, owing to the, extremethinness of the sheets, any unevenness or imperfections in the surfaceof the core would be readily apparent, a detriment that is difficult toovercome, inasmuch as it is uite impossible to produce a core with a perectly smooth surface, even with great care being,y used in the planingiand sanding.

Moreover, wood veneering as practiced commercially, is an expensiveprocess, since the veneer must be carefully trimmed and fitted to makesmooth joints, and due to thickness of the material` the process islargely confined to fiat or plane surfaces, inasmuch as the veneercannot be bent to conform to irregular contours without breakage orsplitting of the fibers, andfmal-r ly lthe ordinary wood veneeredsurface is r su ject'to the same destructive forces that attack anyfinished wood surface, viz: moisture, heat and ordinary wear and tear.

' In accordance with the followin disclosure, however, it is possiblenot on y to use Wood veneers of paper thinnesspsay, from l door as takenon line 2`2 of Figure 1.

, attaching the sheets together.

1930. lSerial No. 460,563.

1/20 to 1/80 of an inch in thickness, in the manufacture of doors andlike products, but to provide the article with a surface equal inappearance and finish to a finely finished piece of natural wood andsuperior in wearing qualities. v

A preferred embodiment of my invention is disclosed in the accompanyingdrawings, in which Figure l is a view in elevation of a finished door ofthe slab type of construction, showing the arrangement of the veneersheets and the graining effect produced. Figure 2 is a view in sectionthrough'the Figure 3 is akview showing the materials assembled andplaced Within a press preparatory to the finishing operation.

Figure 4 is a detail View of a sheet of thin Wood veneer made up oflstrips joined together at their edges, and showing the method ofeliminating checks or blemishes that may occur in the veneer.

Figure 5 is a view in cross section through the sheet of veneer showingthe method of y Figure 6 is an enlarged detailv view of a section of thedoor showing the manner in which the fibrous layer takes up unevennessin the surface of the core and veneer.

Figurev'? is a View in elevation of a panelled door made in accordancewith the invention.

Figure 8 is an enlarged view in section through the door as taken online 8 8 of 85 Figure 7, and

Figure 9 is a view showing the materials assembled in a presspreparatory to the final l pressing operation in the making of a panelled door. Referring to Figures 1 and 2, the door shown is preferablyof the so-called slab type, that is, one of uniform thickness throughoutand having smooth surfaces. The foundation of the door structure is acore 1 preferably of composite structure, made up of small blocks orunits of soft wood la separated by thin strips 1b of Wood Iextendingtransversely of the thickness of the core. A core so constructedillustrates 10Q vfaces of the strips 2, 2 are preferably beveled,

- of manufacture.

so that they flare outwardly to an increased width at their outer orexposed faces, in fact, the width of these strips along their outeredges is substantially equal to the thickness j of the door.

On both sides of the core 1 is a layer Mof compressed fibrous material3, 3 of a substantial thickness, but considerably less than that of thecore. Ihe substance composing the layers'3, 3 is preferably acellulosediber, such as cornstalk or wood lpulp processed into sheets orboards, or in place of an espe'- cially prepared produce, any one ofseveral commercial products known generally as composite board and usedextensively in building operations for wall insulation, may be employed.In .the finished door, as shown in Figure 2, these layers of fibrousmaterials have been subjected to considerably greater pressure thanemployed in Atheir original processing, and consequently have a densityconsiderably greater and a thickness so'mewhat less, than they have intheir natural state; in fact, their nal density may be said to approachthat of a natural soft wood.

The surfaces of the fibrous layers 3, 3 are initially treated with aresinous substance, such as a natural rosin varnish or a solution of asynthetic resin, such as bakelite, the latter being preferred because ofits superior qualities as a moisture and heat resistant. The treatmentof the fibrous layers with the resinous substance will be explained ingreater detail in connection with the process Over the surfaces of thefibrous layers 3, 3 are sheets of ordinary kraft paper 4, 4 which havelikewise been treated or impregnated with a resinous substance, andagain bakelite is preferred, in which case the term bakelizing may beused to describe the treat-- ment. And finally, over the surface of thepaper sheets are the veneering sheets or layers 5, 5 consisting ofpaper-thin wood of any desired kind, such as walnut, mahogany or otherhard and expensive wood used for- As heretofore indiornamental finishes.cated, wood suitable for veneering purposes can be readily producedcommercially in exceedingly thin sheets of from 1/80 to 1/120 of aninchfr about that of ordinary tissue paper, althou h it has been oflittle use in the wood-working art, owing to its extreme thinness andthe diiculty of satisfactorily applying to a surface as a veneer.

This paper-thin veneering material, as in the case of the layer of paper4 lying just below it, is treated with a resin varnish, and preferablybakelite varnish, preparatory to its use, this treatment consisting ofpassing itthrough a bath of varnish or a bakelite solution, and thenbetween pressure' rolls to remove the excess of the solution, andfinally drying it in an oven, the heat driving off the solvent, leavingthe wood thoroughly impregnated with the bakelite, which fills the poresand spaces between the fibers. Because of the extreme t-hinness of thesheets of wood veneer, they are usually handled and treated with thevarnish in a wet or damp condition, so that the drying process alsodrives ofi' the moisture as well as the solvent in thefvarnish, leavingthem quite dry except for a slight tackiness of the surface.

The sheets of the treated wood veneer are ordinarily smaller than thesurface to be covered thereby, and hence it requires several sheetsjoined together to provide the veneer fora large surface area. Thus asshown in Figures l and 4, the veneeringmaterial is cut or trimmed intothe form of strips 5a to extend lengthwise of the door, andassembledintov a single large sheet of a size to cover one side of thedoor. Accordingly the severalv strips 5a are arranged edge to edge andthen joined together-by gummed paper strips 6 applied to theirunderside, as shown in Figures 5 and 6. Also ink handling thesethin-sheets of veneer, cracks or checks 'develop where the fibers split,or imperfections in the wood cause openings to appear, as at 7 W'herethese breaks or checks occur, it is a simple matter to eliminate them byapplying small patches 8 of the same thin veneer underneath and securingthem in place by the gummed strips, care being taken to match thegraining as closely as possible.

Now, as previously explained, the layers v3, 3 of fibrous material arealso treated with us having prepared the sheets of veV j neer and thematerials for the under layers, all cut tothe proper size to correspondto the surfacearea of the corel, they are now assembled on oppositesides of the core preparatory to compression in an especially equippedhydraulic press.

Referring now to Figure 3, the several 13C layers of material are shownin their relative positions between the platens 9, 9 ofthe press, saidplatens being thick plates with passages 9a therethrough for thecirculation of steam and cooling water. Between the platens and theassembled materials are thin plates 10, 10 having their contact surfacescarefully prepared and polished, the degree of polish determining thesurface finish of the completed door.

The materials are assembled in the press with the layers 3, 3 of fibrousmaterialin contact with opposite faces of the core 1,

the sheets of paper 4, 4 over thebrous layable fibrous layer fills thedepression when plied to the core.

ers, and the sheets of Wood veneer 5, 5 over the layers ofl paper. Withthe exception of the layer of fibrous material 3, 3, the several layersare non-yielding, and therefore do not undergo compression or reductionin thickness in the operation. The layers of fibrous material 3, 3,however, are capable of further compression to, say, one-half toone-quarter of their original thickness, and, therefore, are shown asbeing considerably thicker before the pressing operation (Figure 3).These fibrous layers, therefore, provide a yieldable cushion-like plybetween the surface of the core and the outer layer of thin veneer, andserve primarily to com ensate for any unevenness in the surface o thecore, on the one hand, and inequalities in thickness of the woodveneer,I on the other.

For eXample,lif there should be depressions in the core as at a, (Figure6), due to some imperfection in its making, the yieldpressure is appliedWithout transmitting the unevenness to the surface layers. 'Similarlythe fibrous layer presents a resilient foundation for the wood veneer,and again when pressure is applied, the additional thicknesses caused bythe overla ping? f the edges and the application o the patches, togetherwith lthe attaching strips of adhesive paper, are pressed into theresilient surface, with the result that the surface is perfectly smooth,as also shown in Figure 6.

In general, the press operation consists in subjecting the assembledmaterials to pressure and heat under conditions found by eX- perience tobe most satisfactory. Thus, having applied an initial pressure, streamis allowed to circulate through the passages 9a in the platens 9,gradually bringing the temperature up to the point re uired to fuse andcure the bakelite impregnatmg the layers apcreased to a maximum of from200 to .500 pounds per square inch, and maintained for a period of from5 to 15 minutes, whereupon the steam is shut ofi:` and cooling watercirculated through the platens, thereby reducing the temperature toAnormal before the pressure is released. r

The door is then removed from the press,

The pressure is then in` and is ready foruse without any additionalpolishing or finishing. As a result of the pressure and heat treatmentthe several layers of bakelite impregnated materials become firmlycemented together and to the surface of the core, forming in effect acomposite covering Witha surface coating of the wood veneer backed bythe paperand cemented to the fibrous layer. Again, the fused bakelite orresin, as the case may be, forms a hard colorless film, which in thecase -of bakelite in particular, becomes infusible,

moisture and heat-proof, and capable of takingv on the naturalsmoothness and lustre of a polished natural wood surface.

As heretofore stated, the fibrous layers 3, 3 undergo substantialcompression during the pressure treatment, and become quite as dense asthe wood in the core, with slight variations wherever depressions oruneven spots are rectified either in the core or the external layer ofwood veneer. The `fiber layers 3, 3 moreover preferably include a rosinsizing introduced during its preparation, which serves' as a binder asWell as a moisture repellant, and hence there is no tendency o f thefibers to expand after the pressure is removed, to cause subsequentswelling and consequent unevenness of surface. It may be desirable tobevel the edges ofthe fibrous layers 3, 3 at their edges, as at 3a,Figure 3, where they contact with the beveled or fiared edges of theedge strips 2, 2, so there will not be excessive compression at thesepoints. Thus the edges of the door are substantially Wood throughout thefull thickness, this being desirable in order to facilitate the mountingof the hardware, in that, the screws may haver anchorage in the woodrather than the fibrous material, although as a matter of fact thedensity of the fibrous layers is ample to hold the screw l threads.

thicker than the central portion, with por.

tions of varying thicknesses between, thus carrying out the same styleof construction used in all-wood doors, namely, the thicker outer stilesand rails, the thin central panel and an ornamental moulding between.

Consequently the core, 12 in this case 1s made up inthe form of a frameof a Width to provide the lfoundation for the outer stile and railportions of the door and the moulding, leaving a large central openingto be filled by the fibrous layers 13, 13, to form the central panel,these fibrous layers being the same as those described in connectionwith the slab door of Figures 1 and 2. Thus the core 12 in the form of aframe is beveled about `its inner edge to a cross-sectional lcontour ofreduced thickness and conforming/T30 generally to the'stepped or offsetcontour of the moulding-like surface portion surrounding the thinnercentral panel.

Aside from the construction of the core, which otherwise is made up asbefore with the edge strips 14, the layers of fibrous material 13, 18,bakelized paper 15, 15, and thin wood veneer 16, 16, are treated,arranged and assembled upon the core, and subjected to pressure and heattreatment in the press, in the saine manner as previously described.However, there is a difference in the equipment used in the press,namely, the

l substitution of die plates 17, 1T for the flat pressure plates. Thesedie plates have the impressions of the door surface sunk or cut on theiropposed faces after the man-A ner of a molding die, so that when thepressure is applied the materials conform to the impressions, thusproducing the cross section contour of Figure 8, even to thereproduction of miter joints at the corners of the moulding sections.

lt may be stated in this connectionl that the preparation of the sheetsof wood veneer may be somewhat different in the manufacture of panelleddoors than for slab doors,v

since it is the practice to take advantage of the graining to enhancethe appearance. Thus the sheets may be cut into strips and assembled asbefore, with the grain running lengthwise of the stiles and railportions as well as'the moulding portions, and mitered at theirlcorners, while the central panel may have a different arrangement ofgraining or even different coloring, all of which is a matter of designand ornamentation.

The completed door has the same physical characteristics as the slabdoor, with the added features of the central panel composed of the twothicknesses of the fibrous layers compressed together and the numeroussharp bends and angles which the surface coating of wood Veneer makes inreproducing the effect of a moulding about the central-panel. This is anotable feature of the paper-thin veneering, namely, that it is so thinthat it can be bent around sharp cor-f riority of bakelite, as thecementing agent` over glue or other adhesive used in veneering work. Inthe first place, glue does not afford protection to the surface of thearticle, while bakelite not only forms a perfect bond between thelayers, but when cured forms a film impregnating the pores and lfibersof the surface layers of thin veneer and presenting a hard, infusiblecoating which resists heat, moisture and hard wear, and withall takes ona smooth natural finish which cannot be distinguished from a naturalwood finish.

And again, bakelite will withstand high pressures without lessening itsbonding or cementing properties, while glue and other adhesivesarelimited as to pressure that can be applied in adhering surfacestogether since they tend to vbe driven into the materials being joined,leaving the surfaces deficient in adhesion.

The product and process may be modified to the extent of omitting theimpregnation of the thin sheets of wood veneer with the resinousadhesive or bakelite, and depending on the adhesive coating 011 thecoated sheet of paper beneath the veneer to provide the .bond oradhesion of the two. This would be advantageous for some classes ofwork, since the veneered surface would then be in its natural state andcould be later stained or otherwise finished to harmonize with the otherwood work.

Having set forth a preferred embodiment of my invention, I claim:

1. A y'method of constructing doors and the like, consisting of forminga core of soft wood blocks and tapered marginal wood strips to providethe core with an increased thickness at its outer edges, applying layersof compressible fibrous material over the surfaces of said core, thesurfaces of said 'layers having been previously coated with a phenolkcondensation product and their inner marginal portions being beveled tocomplement the taper of said strips, treating sheets` of paper and thinwood veneer with a solution of a phenol condensation product andapplying the same over the layers of fibrous material with the woodveneer outermost, and subjecting the core with the superimposed layersand sheets to heat and pressure.

2. A method of constructing doors and the like, consisting of forming acore of soft wood with tapered marginal wood strips to provide the corewith an increased thickness at its outer edge, applying layers ofcoinpressible fibrous material over the surfaces of said core, the edgesof said layers having been beveled on the inner face to complement thetaper of said marginal strips, applying av slightly beveled tocomplement the taper of said strips, applying layers of paper and anouter layer of thin Woodl veneer upon each layer of compressible fibrousmaterial, the contacting surfaces thereof having been previously treatedwith a resinous varnish and dried, and subjecting the assembledmaterials to heat and pressure sulicient to bond the layers together andreduce the Whole to a predetermined thickness.

4. A method of construct-ing doors and thelike, consisting of forming acore of soft Wood, providing said core with marginal Wood strips taperedto an increased thickness at their outer edges, applying layers ofcompressible fibrous material over the surfaces of said core, themarginal portions of said layers having been previously tapered to areduced thickness to complement the taper of the marginal strips of saidcore, applying sheets of paper over the surface of said layers offibrous material and layers of thin Wood veneer over said layers of paper, the surfaces of said core and/or the several superimposed layersappliedthereto having been treated With a resinous adhesive substanceand subjecting the assembled materials to heat and pressure.

Signed at Dubuque, Iowa, this 7th day of June, 1930.

EMIL C. LOETSCHER.

